When is the Christmas delivery cut-off at the biggest cycling retailers?

Competitive Cyclist has several shipping options that all come with their own cut-off date.
For standard shipping, you must order by December 15, 3pm MST.
Two-day shipping is still available up until December 20, 1pm MST.
Finally, you can get next-day delivery until December 21, 1pm MST.

BackCountry is partnered with Competitive Cyclist and therefore has almost the same deadlines as listed above.
For standard shipping, you must order by December 15, 3pm MST.
Two-day shipping is still available up until December 20, 1pm MST.
Finally, you can get next-day delivery until December 21, 12pm MST.

Jenson USA is currently not advertising its cut-off date for Christmas delivery.

REI recommends ordering by 9am PT on December 19 for delivery in time for Christmas.
Alternatively, you can have your order delivered to your nearest REI store, with an estimated arrival date quoted at order.
REI also offers curbside pickup at many locations and will send you an email once your order is ready to collect.

Mike's Bikes is offering in-store pick-up on items ordered online until December 18, 1pm PST. 

Rapha has listed its cut-off shipping dates for US customers as follows:

The standard delivery date for US orders for Christmas 2023 has passed, but if you're prepared to pay $10 for express delivery or are spending over $800, Rapha quotes a cut-off time of December 20, 3pm UK time.

Amazon lists the expected delivery date with its different shipping options at check-out. The easiest way to expedite things is if you're signed up for Amazon Prime, which offers free same day delivery within urban areas. You'll see an Order By time quoted to ensure same day delivery and the expected delivery date if same day delivery isn't available for an item.

Wiggle has ceased to accept international orders. 

In the UK, the cut-off for free/standard delivery is December 15, but you can still get paid-for next day delivery on orders placed by December 20.

Chain Reaction Cycles, as with its partner brand Wiggle, has stopped servicing international orders. 

In the UK, the cut-off for free/standard delivery is December 15, but you can still get paid-for next day delivery on orders placed by December 20.

Amazon, as in the US, lists the expected Get It By delivery date for its UK customers for its different shipping options at check-out.
Amazon Prime can speed things up, with free same day delivery within urban areas. You'll see an Order By time quoted to ensure same day delivery and the expected delivery date if same day delivery isn't available for an item.

Rapha has listed its cut-off shipping dates for UK customers as follows:

In the UK, standard delivery is available until December 17 (time not specified).
Express delivery is available until 3pm on December 21.

Tredz will deliver your order before Christmas if it's placed by December 19.
It has a paid-for next day delivery service which might speed things up if you're worried you may have cut it too close.

Sigma Sports has a last order date of December 15 for standard delivery. There are later dates for other options though, as follows:
- Priority 1st Class delivery until December 18.
- DPD next day until December 21.
- Weekend delivery until December 22.

Cyclestore is currently not advertising its cut-off date for Christmas delivery. It quotes 2 -3 days delivery times,with faster delivery options available, but this is likely to be longer in the run-up to Christmas.

Evans Cycles has provided a full list of cut-off dates for its pre-Christmas deliveries.
Standard delivery is available on bikes ordered by December 15, and the next day delivery cut-off is December 21.
Clothing and accessories can be ordered until December 19, with next day delivery available until December 22.

Rutland Cycling is currently not advertising a specific cut-off date for Christmas delivery, but will indicate expected delivery date on checkout.

ProBikeKit is currently not advertising its cut-off date for Christmas delivery.

99 Bikes (formerly Hargroves Cycles) doesn't specify a last order date on its site.

Pure Electric has a cut-off date of December 21 for pre-Christmas delivery.